include/effects/SkBlurMaskFilter.h

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkBlurMaskFilter_DEFINED
#define SkBlurMaskFilter_DEFINED

// we include this since our callers will need to at least be able to ref/unref
#include "SkMaskFilter.h"
#include "SkScalar.h"
#include "SkBlurTypes.h"

class SK_API SkBlurMaskFilter {
public:
    /**
     *  If radius > 0, return the corresponding sigma, else return 0. Use this to convert from the
     *  (legacy) idea of specify the blur "radius" to the standard notion of specifying its sigma.
     */
    static SkScalar ConvertRadiusToSigma(SkScalar radius);

    enum BlurFlags {
        kNone_BlurFlag = 0x00,
        /** The blur layer's radius is not affected by transforms */
        kIgnoreTransform_BlurFlag   = 0x01,
        /** Use a smother, higher qulity blur algorithm */
        kHighQuality_BlurFlag       = 0x02,
        /** mask for all blur flags */
        kAll_BlurFlag = 0x03
    };

    /** Create a blur maskfilter.
     *  @param style    The SkBlurStyle to use
     *  @param sigma    Standard deviation of the Gaussian blur to apply. Must be > 0.
     *  @param flags    Flags to use - defaults to none
     *  @return The new blur maskfilter
     */
    static SkMaskFilter* Create(SkBlurStyle style, SkScalar sigma, uint32_t flags = kNone_BlurFlag);

    /** Create an emboss maskfilter
        @param blurSigma    standard deviation of the Gaussian blur to apply
                            before applying lighting (e.g. 3)
        @param direction    array of 3 scalars [x, y, z] specifying the direction of the light source
        @param ambient      0...1 amount of ambient light
        @param specular     coefficient for specular highlights (e.g. 8)
        @return the emboss maskfilter
    */
    static SkMaskFilter* CreateEmboss(SkScalar blurSigma, const SkScalar direction[3],
                                      SkScalar ambient, SkScalar specular);

    SK_ATTR_DEPRECATED("use sigma version")
    static SkMaskFilter* CreateEmboss(const SkScalar direction[3],
                                      SkScalar ambient, SkScalar specular,
                                      SkScalar blurRadius);

    SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()

private:
    SkBlurMaskFilter(); // can't be instantiated
};

#endif